//
// 高精度X低精度
// Created by Administrator on 2024/5/10.
//

#include <iostream>
#include <vector>

using namespace std;

// 计算10的幂次
int powTen(int n)
{
    int ret=1;
    for (int i = 1; i <= n; ++i)
    {
        ret*=10;
    }
    return ret;
}

string addTwoString(string a, string b)
{
    string ret;
    if (a.size() < b.size())
        swap(a, b);
    while (a.size() - b.size() > 0)
        b = "0" + b;
    int len = a.size();
//    cout<<a<<endl;
//    cout<<b<<endl;
    int next = 0;
    for (int i = len - 1; i >= 0; --i)
    {
        int cur = next + a[i] - '0' + b[i] - '0';
        if (cur > 9)
        {
            cur -= 10;
            next = 1;
        } else
            next = 0;
        string t = to_string(cur);
        ret=t+ret;
    }
    if(next==1)
        ret="1"+ret;
    return ret;
}

int main()
{
    string aa="856309"; int bb = 25; // 21407725
//    vector<int> ret;
    string ret,tt="0";
    for (int i = aa.size()-1,j=0; i >= 0 ; --i,++j)
    {
        int t = (aa[i]-'0')*bb*int(powTen(j));
        tt=addTwoString(tt,to_string(t));
    }
    cout<<tt<<endl;
    return 0;
}